JotSpot is now part of Google. This application crated by Joe Kraus and Graham Spencer -- co-founders of Excite -- is almost a hybrid wiki / web office suite that will be a great fit for Google. The application has "page types" that can be easily created by users: Group directory, file cabinent, blog, forum, group calendar, photo gallery, poll and to-do list.
Sine new registrations have been disabled until further notice, the JotSpot gallery page contains screenshots and descriptions of most features you can find in the application. Read more about the acquisition here and here.